Large-area and uniform transparent electrodes fabricated by polymethylmethacrylate-assisted spin-coating of silver nanowires on rigid and flexible substrates

We have proposed a full-solution polymethylmethacrylate (PMMA)-assisted spin-coating method for uniformly distributing silver nanowires, which are carried in PMMA, on both rigid and flexible substrates as transparent electrodes. High optical transmittance (similar to 0.91, much better than that of a 80 nm thick ITO that is typically applied to solar cells), good electrical conductivity (similar to 15 Omega/sq on average, comparable to that of ITO) and long-term stability have been demonstrated for the devices on 4 '' glass substrates, which are also better than the devices fabricated without the assistance of PMMA. The mechanism is presented through systematic investigation of the effects of two key processing parameters, i.e., the volume ratio of the Ag NWs in ethanol to the PMMA, and the second rotary speed of the spin-coating process. This method has been extended to flexible substrates. Good uniformity is also achieved over a large area of 5 cm x 5 cm. A simple application demonstration indicates again the great potential of our method for mass production of Ag NW networks, which are likely to replace ITO as transparent electrodes. (C) 2015 Optical Society of America.